Process for the production of beta-methylglutaconic acid dinitrile



United States Patent PROCESS FOR THE PRODUCTION OF B-NIETHYL- GLUTACONIC ACID DINlTRlLE Peter Kurtz, Leverkusen-Bayerwerk, Germany, assignor to Farbenfabriken Bayer Aktiengesellscliaft, Leverkusen, Germany, a corporation of Germany No Drawing. Application June 29, 1955 Serial No. 518,957

Claims priority, application Germany June 29, 1954 2 Claims. (Cl. 260-4653) This invention relates to B-methyl-glutaconic acid dinitrile and to a process for producing the same.

It is an object of the present invention to provide a novel process for the production of fl-methyl-glutaconic acid dinitrile. Other objects will appear hereinafter.

These objects are attained in accordance with the present invention by treating fl-methylene-glutaric acid dinitrile in an inert diluent with small amounts of alkaline reacting compounds for a short period of time at temperatures below 80 C.

As diluent in which the process of the invention may be carried out, there may be used those diluents which do not react with the compounds applied in the process of the invention, for example ethanol and aqueous ethanol. Benzene has proved to be especially suited.

Suitable alkaline compounds are, e. g., the alkali metal hydroxides, the alkali metal alcoholates and phenolates, and amines of suflicient basicity as, for example, piperidine. These compounds are added in general in amounts of about 0.2 to 2 mol percent calculated on fi-methylene-glutaric acid dinitrile, even though other quantities are eifective and may be used occasionally with advantage.

In practicing the process of the invention, the reaction mixture is slightly warmed to start the reaction. Since the reaction proceeds under evolution of heat, care has to be taken that the reaction temperature does not exceed 80 C. Furthermore, the reaction should be finished within about minutes, since otherwise the fl-methylene- 2,832,797 Patented Apr. 29, 1958 glutaric acid dinitrile and the p-methyl-glutaconic acid dinitrile formed are dimerized. V

The fi-methyl-glutaconic acid dinitrilecan be used as intermediate compound, e. g. upon saponification and esterification in the process'of British patent specification No. 722,911.

The following examples further illustrate the invention without, in any way, limiting it.

Example 1 500 grams of p-methylene-glutaric acid dinitrile (M. P. 49 to 50 C.) are dissolved in 600 cc. of dry benzene. Upon addition of 0.5 gram of phenol, the mixture is warmed to 36 C. and then 3 grams of sodium phenolate are added. The reaction proceeds under evolution of heat while the temperature of the reaction mixture rises to 71 C. As soon as the temperature drops, the reaction mixture is cooled. Upon filtration, the solution is washed with 200 cc. of dilute hydrochloric acid and subsequently with water. Then the reaction mixture is dried over sodium sulfate, the benzene evaporated and the residue fractionated. Thus, fl-methyl-glutaconic acid dinitrile is obtained. B. P. 81 to 89 C./0.005 mm. n =1.4738. Yield: 427.5 gramsof the theoretical.

Furthermore, a residue of 56.5 grams of a viscous resin is obtained.

Example 2 In a series of experiments each time 10 grams of B- methylene-glutaric acid dinitrile are dissolved in 10 cc. of a diluent (benzene, ethanol or aqueous ethanol) and the mixture warmed up to about 40 C. Then, mol of an alkaline catalyst is added and the reaction temperature determined to which the mixture is heated. As soon as the temperature drops, the reaction mixture is cooled. If benzene is used as diluent, the solution is washed with slightly acid water, dried over sodium sulfate, the benzene evaporated and the residue fractionated. If alcohol is used as diluent, slightly acidified water is added, the precipitated oil extracted with ether, the ethereal solution dried over sodium sulfate, the ether evaporated and the residue fractionated.

The results are given in the following table.

CHQCN CH-CN CH:=C CH:C

CHICN OHr-CN Raise of Reaction Product Assay No. Solvent Mixture Catalyst Tempernu Residue of the ature, Distillation C. B. P. grams 1 benzene 0.2 g. ON8 4164 124-130 0.]11-.- 8.4 1. 4732 0.6 gram resin.

2 -do 0.14 g pyridine none 3 do 0.14 g pyridine I none 4 do 0.17 g piperidine 40-52 125131 O./10 9. 8 1. 4733 residue 0.2 gram.

ethanol 0.2 g. 0N8 39-53 124-130 C./10 6. 9 1. 4740 2.3 grams resin.

do 0.1 g. OHa-O-Na 4360 127-138 0.112-.. 6.3 1. 4725 1.6 grams resin. do 0.11 g. KCN--..- 8 none 125-136 (1/10... 4.5 1. 4733 ethanol-E13 1? 4 :1 43-56 125130 0.]10- 6. 5 1. 4723 2.3 grams resin.

1 Heated tor 10 minutes to 80 0.; starting material reeovered =10.0 grams. 1 Heated for 5 hours to 80 0.; starting material recovered=9.9 grams. 3 Heated for 10 minutes to 80 0.; residne=4.3 grams resin.

3 4 I claim: 2. A process as claimed in claim 1, in which a member 1. Process for the production of fi=methylrglutaconic selected from the; group consisting, of. benzene, ethanol acid dinitrile which comprises treating B-methylene gluand aqueous ethanol is used as inert diluent.

taric acid dinitrile in an inert diluent with an alkaline References Cited in the file of this patent reacting compound which is selected from the group consisting of the alkali metal hydroxides, the alkali FOREIGN PATENTS metal alcoholates and the alkali metal phenolates and 702,275 Great Britain Jan. 13, 1954 p ne s ine tor; a short perio Qt t me at temp rature below 80 C. and recovering theJS-rnethyhglutaconic aeid ini r le fn aed- 

1. PROCESS FOR THE PRODUCTION OF B-METHYL-GLUTACONIC ACID DINITRILE WHICH COMPRISES TREATING B-METHYLENE GLUTARIC ACID DINITRILE IN AN INERT DILUENT WITH AN ALKALINE REACTING COMPOUND WHICH IS SELECTED FROM THE GROUP CONSISTING OF THE ALKALI METAL HYDROXIDES, THE ALKALI METAL ALCOHOLATES AND THE ALKALI METAL PHENOLATES AND PIPERIDINE FOR A SHORT PERIOD OF TIME AT TEMPERATURES BELOW 80*C. AND RECOVERING THE B-METHYL-GLUTACONIC ACID DINITIRLE FORMED. 